Cooling system



June 28, 1966 J P P 3,257,818

COOLING SYSTEM Filed July 28, 1964 INVENTOR. J AM E s A. FAPAPANU VMKMATTORNEY United States Patent 3,257,818 COOLING SYSTEM James A.Papapanu, Syracuse, N.Y., assignor to Carrier Corporation, Syracuse,N.Y., a corporation of Delaware Filed July 28, 1964, Ser. No. 385,630 4Claims. (Cl. 62-98) This invention relates to a system and method forproviding cooling wherein a cooling medium comprising a mixture of waterand ice particles is circulated to heat exchangers in areas having acooling requirement.

It is common practice to circulate a cooling medium such as chilledwater from a refrigeration machine to heat exchangers located in areashaving a cooling requirement. As the chilled water is circulated throughthe heat exchanges in heat exchange relation with a medium and relatedpiping for carrying the mixture to the heat exchangers may be smallerthan comparable components required for circulating chilled water inkeeping with conventional practice.

It is a primary object of this invention to provide a new andimprovedsystem and method for providing refrigeration and, more particularly,cooling to an area having a cooling requirement.

. Another object is to provide a new and improved system and method forcooling wherein a chilled medium comprising a mixture of water and iceparticles is utilized for cooling a load.

A more specific object is provision of a new and improved cooling'systemincludinga heat exchanger for cooling a load, and a refrigerationmachine for providing a chilled medium comprising a mixture of water andice particles and circulating the chilled medium through the heatexchanger so that the temperature throughout the heat exchanger remainssubstantially constant, generally at the freezing temperature of theWater, as the ice particles melt to cool the load.

Another more specific object of this invention is the provision in acooling system including a heat exchanger for cooling a load, of a newand improved method of providing cooling including forming a chilledmedium comprising a mixture of Water and ice particles to provide amedium temperature at about the freezing temperature of the water, andpassing the chilled medium through the heat exchanger to cool the load,so that the temperature of the chilled medium remains substantiallyconstant and about the freezing temperature of Water throughout the heatexchanger.

These and other objects of this invention Will become more apparent byreferring to the following detailed description and accompanying drawingwhich is a diagrammatic view, partially in cross-section, illustrating apre ferred embodiment of a cooling system embodying features of theinvention.

As is more fully described in a copending United States patentapplication of Louis H. Leonard for a Meth .od and Apparatus for Heatingand CooIing, Serial No.

112,679, and filed May 25, 1961, the drawing illustrates a directcontact type evaporator 11 which provides a container from whichrefrigerant vapor is withdrawn through a suction line 12 by means of aturbocompressor 13 and,

3,257,818 Patented June 28, 1966 more particularly, a centrifugalcompressor section 14 thereof. The refrigerant vapor is forwardedthrough a high pressure line 15 to a refrigerant condenser 16 foraccumulation of condensed refrigerant vapor. Refrigerant condensate inthe condenser 16 passes a float valve 17 and through a refrigerantcondensate line 18 into a jet ejector or pump 19 and then through asupply line 20 to spray header 21 in the evaporator 11. Suitableexpansion means provide a refrigerant flow restriction in the path ofrefrigerant returned from the condenser to the evaporator and maycomprise the restricted throat portion of the venturi in ejector 19,alone or in combination with the float valve 17, or the return line 18may be sized to provide the required restriction.

A chilled medium or heat exchange liquid in the lower portion of theevaporator 11 is passed through a chilled medium discharge line 22, asby a chilled medium pump 23, and then through 21 leaving trunk line 24to an external heat exchanger means 25, for example one or more heatexchangers 26 in one or more areas, as rooms, having a' coolingrequirement. Thus the heat exchanger means 25 provides cooling tosatisfy a cooling requirement and may be located in the path of air tobe conditioned and circulated to the room. From the heat exchanger means25 the heat exchange liquid passes through a return trunk line 27 to therestricted throat of the ejector 19 and is mixed with the refrigerantreturning from the refrigerant condenser 16 and passes through thesupply line 20 and the spray header 21 into the evaporator 11 forre-evaporation of the refrigerant and re-cooling of the heat exchangeliquid.

A suitable refrigerant for use in the system should be substantiallyimmiscible and completely stable with water. Particularly, therefrigerant should not react with water or decompose to form corrosivecompounds which are a major source of corrosion difficulties in manycooling systems. In addition, the vapor pressure of the refrigerant atoperating temperatures should be substantially greater than that ofwater so that it readily vaporizes in preference to water in the directcontact evaporator 11. One particularly suitable refrigerant for thesystem is refrigerant I C318 having the formula C 1 and known asoctafluorocy-clobutane. This refrigerant has a relatively high molecularweight and only a minimum head need be developed by the compressortoadequately cool the water in the evaporator 11 for a given condensingtemperature.

Since the refrigerant passing through the ejector 19 is in intimateassociation with the water or other heat exchange liquid, the two fluidspresent a relatively large area of surface contact for effective heattransfer to take place when they are sprayed through the spray header 21in the evaporator 11. This results in effective cooling and theformation of ice particles in the body of water in the evaporatorvessel.

A steam generator 30, for example a boiler, having burner 31 forproviding a gas flame, or another suitable heat source, provides steampower fluid through a steam line 32 to a turbine section 33 of theturbocompressor 13. Discharged steam from the turbine 33 passes througha steam discharge line 34 to a steam condenser 35 from which the steamcondensate is pumped through a steam condensate line 36 by a steamcondensate pump 37 in the line 36 and back to the steam generator 30.The pumps 23 and 37 may be driven by a common motor '38.

Tur'bocompressor output is controlled by regulating the steam output ofthe steam generator 30, as by a modulating fuel valve 39 which controlsthe supply of gas or other fuel passing through a fuel supply line 40 tothe generator burner 31, to regulate the supply of steam to the turbine33 and therefore the cooling capacity of the system. Thus, by adjustingthe valve 39, the refrigerant output of the turbocompressor 13 may beadjusted to the cooling -percent by weight of ice particles to water.

demand required of the heat exchanger means 25 for providing a chilledmedium comprising a mixture of water and ice particles. This mixture iscirculated by the chilled medium pump 23 through the heat exchangermeans 25 and back to the evaporator.

In order to pump the mixture of water and ice particles while avoidingexcessive wear and errosion of the .pump 23 and connecting piping, as22, 24 and 27, the size of the ice particles may be regulated. Whileother sizes and proportions may be suitable depending on particularcircumstances, it has been found preferable to provide discrete iceparticles up to a size equivalent by weight to a sphere having adiameter of about one hundred microns, and when a centrifugal pump isused, the mixture containing up to about ten (and possibly up tothirteen) A solution of a salt, such as brine, or a solution of waterand glycol, for example, may be utilized in lieu of relatively purewater in the mixture, so that the freezing point of the liquid is belowthat of the ice particles, to more readily form the ice particles. Inorder to effectively prevent the ice particles from agglomerating andadhering to parts of the system, the mixture may be maintained in motionthroughout the system as by operation of the chilled medium pump 23.

A mixture of water and ice particles may alternatively be formed asdescribed in a United States Letters Patent of Carlyle M. Ashley andCyrus M. Bosworth, No. 3,070,969, and granted January 1, 1963.

The mixture of water and ice particles may be such that no rise intemperature occurs as the chilled medium passes through the heatexchanger means 25, so that the size of the heat exchangers 26 and therelated piping may be reduced over that required for the same coolingcapacity using conventional chilled water.

To summarize the operation of the system, water and refrigerant issprayed in intimate association from the spray header 21 into theevaporator 11. The compressor output may be regulated to providesuflicient refrigerant flow and a reduced pressure within the evaporator11 to facilitate vaporization of the refrigerant for forming thedescribed discrete ice particles in the body of liquid within theevaporator. The chilled medium pump 23 keeps the mixture moving throughthe system to retard adherence of the ice particles to each other or toparts of the system, and circulates the mixture through the heatexchanger means 25 so that on melting the latent heat of the iceparticles substantially increases the cooling capacity of the system.

While a preferred embodiment of. the invention has been described andillustrated, it will be understood that the invention is not limitedthereto since it may be otherwise embodied within the scope of thefollowing claims.

I claim:

1. In a cooling system, the combination comprising, heat exchanger meansfor cooling a load, and refrigeration means comprising a direct contactevaporator for containing a refrigerant and water, and saidrefrigeration means further comprising means for spraying saidrefrigerant and said water in intimate association with each other intosaid evaporator and vaporizing said refrigerant and providing a chilledmixture of water and ice particles and means for passing said mixturethrough said heat exchanger means, whereby the temperature throughoutsaid heat exchanger means remains substantially constant generally atthe freezing temperature of water as the ice particles melt to cool theload.

2. In a cooling system, the combination comprising, heat exchanger meansfor cooling a load, refrigeration means including, a direct contactevaporator in circuit with said heat exchanger means, means for sprayingwater and a refrigerant in intimate association with each other intosaid evaporator to form a chilled medium of a mixture of water and iceparticles of a size equivalent by volume to a sphere having a maximumdiameter of about one hundred microns and a maximum of about ten percentby weight of said ice particles to water, and a pump in circuit betweensaid evaporator and said heat exchanger means for circulating saidmedium therebetween to cool said load, whereby the temperature of themixture remains substantially constant at about the freezing'temperatureof water as the ice particles melt while passing through said heatexchanger means.

3. In a system including heat exchanger means for cooling a load, amethod of providing cooling comprising the steps of, forming a chilledmedium comprising a mixture of water and ice particles to provide amedium temperature at about the freezing temperature of the water byspraying water and refrigerant in intimate association with each otherwhen sprayed, to form said ice particles, and passing said chilledmedium through said heat exchanger means to cool said load, whereby thetemperature of the chilled medium remains substantially constant atabout said freezing temperature as said ice particles melt while passingthrough said heat exchanger means.

4. In a system including heat exchanger means for cooling a load, amethod of providing cooling comprising the steps of, forming a chilledmedium comprising a mixture of water and ice particles of a sizeequivalent by volume to a sphere having a diameter of about one hundredmicrons and a maximum of about ten percent by weight of said iceparticles to water, to provide a medium temperature at about thefreezing temperature of the water, and passing said chilled mediumthrough said heat exchanger means to cool said load, whereby thetemperature of the chilled medium remains substantially constant atabout said freezing temperature as said ice particles melt while passingthrough-said heat exchanger means.

References Cited by the Examiner UNITED STATES PATENTS 310,025 12/1884Brewer 62121 1,712,568 5/1929 Kritzer 62185 1,976,204 10/1934 Voorheeset al. 2,089,886 8/1937 Friedrich 62185 2,101,953 12/1937 Oman 62434 X2,349,671 5/1944 Newton 62333 X 2,440,930 5/ 1948 Camilli et al 62502 X2,722,108 11/1955 Hailey 6259 X 2,751,762 6/1956 Colton 62114 X2,975,609 3/1961 Allander et a1 6258 X 3,132,096 5/1964 Walton 6258 X3,137,554 6/1964 Gilliland 6258 FOREIGN PATENTS 558,857 9/1932 Germany.588,566 11/1933 Germany.

ROBERT A. OLEARY, Primary Examiner.

LLOYD L. KING, MEYER PERLIN, Examiners.

1. IN A COOLING SYSTEM, THE COMBINATION COMPRISING, HEAT EXCHANGER MEANSFOR COOLING A LOAD, AND REFRIGERATION MEANS COMPRISING A DIRECT CONTACTEVAPORATOR FOR CONTAINING A REFRIGERANT AND WATER, AND SAIDREFRIGERATION MEANS FURTHER COMPRISING MEANS FOR SPRAYING SAIDREFRIGERANT AND SAID WATER IN INTIMATE ASSOCIATION WITH EACH OTHER INTOSAID EVAPORATOR AND VAPORIZING SAID REFRIGERANT AND PROVIDING A CHILLEMIXTURE OF WATER AND ICE PARTICLES AND MEANS FOR PASSING SAID MIXTURETHROUGH SAID HEAT EXCHANGER MEANS, WHEREBY THE TEMPERATURE THROUGHOUT